"Internet Relay Chat (IRC) provides a way of communicating in real time with people from all over the world. It consists of various separate networks of IRC servers, machines that allow users to connect to IRC. IRC is very similar to text messaging, but designed around communicating with large groups of users instead of one-on-one." [ref]

IRC is an open standard, thus there are many independently operated IRC networks. Nearly every open source project has its own IRC channel(s) for user support or development chatter. Have a question about GNOME? Head over to the #gnome channel on irc.gnome.org. Have a question about Linux? Head over to #linux on irc.freenode.net. We cannot possibly list every channel and network, but here is a list of IRC search engines: